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<title>htmLawed documentation | htmLawed PHP software is a free, open-source, customizable HTML input purifier and filter</title>
  <span class="toc-item"><a href="#s2.6"><span class="item-no">2.6</span>  Use without modifying old <span class="term">kses()</span> code</a></span><br />
  <span class="toc-item"><a href="#s2.7"><span class="item-no">2.7</span>  Tolerance for ill-written HTML</a></span><br />
  <span class="toc-item"><a href="#s2.8"><span class="item-no">2.8</span>  Limitations & work-arounds</a></span><br />
-  <span class="toc-item"><a href="#s2.9"><span class="item-no">2.9</span>  Examples</a></span><br />
+  <span class="toc-item"><a href="#s2.9"><span class="item-no">2.9</span>  Examples of usage</a></span><br />
<span class="toc-item"><a href="#s3"><span class="item-no">3</span>  Details</a></span><br />
  <span class="toc-item"><a href="#s3.1"><span class="item-no">3.1</span>  Invalid/dangerous characters</a></span><br />
  <span class="toc-item"><a href="#s3.2"><span class="item-no">3.2</span>  Character references/entities</a></span><br />
<div id="body">
<br />
-<div class="comment">htmLawed_README.txt, 16 July 2009<br />
-htmLawed 1.1.8.1, 16 July 2009 <br />
+<div class="comment">htmLawed_README.txt, 19 January 2015<br />
+htmLawed 1.1.19, 19 January 2015<br />
Copyright Santosh Patnaik<br />
-GPL v3 license<br />
+Dual licensed with LGPL 3 and GPL 2+<br />
A PHP Labware internal utility - <a href="http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed">http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed</a> </div>
<br />
<a name="s1" id="s1"></a><span class="item-no">1</span>  About htmLawed
</h2><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed is a highly customizable single-file PHP script to make text secure, and standard- and admin policy-compliant for use in the body of HTML 4, XHTML 1 or 1.1, or generic XML documents. It is thus a configurable input (X)HTML filter, processor, purifier, sanitizer, beautifier, etc., and an alternative to the <a href="http://tidy.sourceforge.net">HTMLTidy</a> application.<br />
+  htmLawed is a PHP script to process text with HTML markup to make it more compliant with HTML standards and administrative policies. It works by making HTML well-formed with balanced and properly nested tags, neutralizing code that may be used for cross-site scripting (XSS) attacks, allowing only specified HTML tags and attributes, and so on. Such <em>lawing in</em> of HTML in text used in (X)HTML or XML documents ensures that it is in accordance with the aesthetics, safety and usability requirements set by administrators.<br />
<br />
-  The <em>lawing in</em> of input text is needed to ensure that HTML code in the text is standard-compliant, does not introduce security vulnerabilities, and does not break the aesthetics, design or layout of web-pages. htmLawed tries to do this by, for example, making HTML well-formed with balanced and properly nested tags, neutralizing code that may be used for cross-site scripting (<span class="term">XSS</span>) attacks, and allowing only specified HTML elements/tags and attributes.<br />
+  htmLawed is highly customizable, and fast with low memory usage. Its free and open-source code is in one small file, does not require extensions or libraries, and works in older versions of PHP as well. It is a good alternative to the HTML <a href="http://tidy.sourceforge.net">Tidy</a> application.<br />
<div class="sub-section"><h3>
<a name="s1.1" id="s1.1"></a><span class="item-no">1.1</span>  Example uses
<br />
  *  <strong>beautify</strong> or <strong>compact</strong> HTML  ^~`<br />
<br />
-  *  <strong>restrict elements</strong>  ^~`<br />
-  *  proper closure of empty elements like <span class="term">img</span>  ^`<br />
+  *  can <strong>restrict elements</strong>  ^~`<br />
+  *  ensures proper closure of empty elements like <span class="term">img</span>  ^`<br />
  *  <strong>transform deprecated elements</strong> like <span class="term">u</span>  ^~`<br />
  *  HTML <strong>comments</strong> and <span class="term">CDATA</span> sections can be permitted  ^~`<br />
  *  elements like <span class="term">script</span>, <span class="term">object</span> and <span class="term">form</span> can be permitted  ~<br />
  *  remove <strong>invalid attributes</strong>  ^`<br />
  *  element and attribute names are <strong>lower-cased</strong>  ^<br />
  *  provide <strong>required attributes</strong>, like <span class="term">alt</span> for <span class="term">image</span>  ^`<br />
-  *  <strong>transform deprecated attributes</strong>  ^~`<br />
+  *  <strong>transforms deprecated attributes</strong>  ^~`<br />
  *  attributes <strong>declared only once</strong>  ^`<br />
<br />
  *  <strong>restrict attribute values</strong>, including <strong>element-specifically</strong>  ^~`<br />
  *  ensure <strong>unique</strong> <span class="term">id</span> attribute values  ^~`<br />
  *  <strong>double-quote</strong> attribute values  ^<br />
  *  lower-case <strong>standard attribute values</strong> like <span class="term">password</span>  ^`<br />
+  *  permit custom, non-standard attributes as well as custom rules for standard attributes  ~`<br />
<br />
  *  <strong>attribute-specific URL protocol/scheme restriction</strong>  *~`<br />
  *  disable <strong>dynamic expressions</strong> in <span class="term">style</span> values  *~`<br />
<br />
  *  remove <strong>null</strong> characters  *<br />
  *  neutralize potentially dangerous proprietary Netscape <strong>Javascript entities</strong>  *<br />
-  *  replace potentially dangerous <strong>soft-hyphen</strong> character in attribute values with spaces  *<br />
+  *  replace potentially dangerous <strong>soft-hyphen</strong> character in URL-accepting attribute values with spaces  *<br />
<br />
  *  remove common <strong>invalid characters</strong> not allowed in HTML or XML  ^`<br />
  *  replace <strong>characters from Microsoft applications</strong> like <span class="term">Word</span> that are discouraged in HTML or XML  ^~`<br />
<a name="s1.3" id="s1.3"></a><span class="item-no">1.3</span>  History
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed was developed for use with <span class="term">LabWiki</span>, a wiki software developed at PHP Labware, as a suitable software could not be found. Existing PHP software like <span class="term">Kses</span> and <span class="term">HTMLPurifier</span> were deemed inadequate, slow, resource-intensive, or dependent on external applications like <span class="term">HTML Tidy</span>.<br />
+  htmLawed was created in 2007 for use with <span class="term">LabWiki</span>, a wiki software developed at PHP Labware, as a suitable software could not be found. Existing PHP software like <span class="term">Kses</span> and <span class="term">HTMLPurifier</span> were deemed inadequate, slow, resource-intensive, or dependent on an extension or external application like <span class="term">HTML Tidy</span>. The core logic of htmLawed, that of identifying HTML elements and attributes, was based on the <span class="term">Kses</span> (version 0.2.2) HTML filter software of Ulf Harnhammar (it can still be used with code that uses <span class="term">Kses</span>; see <a href="#s2.6">section 2.6</a>.).<br />
<br />
-  htmLawed started as a modification of Ulf Harnhammar's <span class="term">Kses</span> (version 0.2.2) software, and is compatible with code that uses <span class="term">Kses</span>; see <a href="#s2.6">section 2.6</a>.<br />
+  See <a href="#s4.3">section 4.3</a> for a detailed log of changes in htmLawed over the years, and <a href="#s4.10">section 4.10</a> for acknowledgements.<br />
</div>
<div class="sub-section"><h3>
<a name="s1.4" id="s1.4"></a><span class="item-no">1.4</span>  License & copyright
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed is free and open-source software licensed under GPL license version <a href="http://www.gnu.org/licenses/gpl-3.0.txt">3</a>, and copyrighted by Santosh Patnaik, MD, PhD.<br />
+  htmLawed is free and open-source software dual copyrighted by Santosh Patnaik, MD, PhD, and licensed under LGPL license version <a href="http://www.gnu.org/licenses/lgpl-3.0.txt">3</a>, and GPL license version <a href="http://www.gnu.org/licenses/gpl-2.0.txt">2</a> (or later).<br />
</div>
<div class="sub-section"><h3>
<a name="s1.5" id="s1.5"></a><span class="item-no">1.5</span>  Terms used here
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  *  <em>administrator</em> - or admin; person setting up the code to pass input through htmLawed; also, <em>user</em><br />
+  In this document, only HTML body-level elements are considered. htmLawed does not have support for head-level elements, <span class="term">body</span>, and the frame-level elements, <span class="term">frameset</span>, <span class="term">frame</span> and <span class="term">noframes</span>, and these elements are ignored here.<br />
+<br />
+  *  <em>administrator</em> - or admin; person setting up the code that utilizes htmLawed; also, <em>user</em><br />
  *  <em>attributes</em> - name-value pairs like <span class="term">href="http://x.com"</span> in opening tags<br />
-  *  <em>author</em> - <em>writer</em><br />
+  *  <em>author</em> - see <em>writer</em><br />
  *  <em>character</em> - atomic unit of text; internally represented by a numeric <em>code-point</em> as specified by the <em>encoding</em> or <em>charset</em> in use<br />
  *  <em>entity</em> - markup like <span class="term">&gt;</span> and <span class="term">&#160;</span> used to refer to a character<br />
  *  <em>element</em> - HTML element like <span class="term">a</span> and <span class="term">img</span><br />
-  *  <em>element content</em> -  content between the opening and closing tags of an element, like <span class="term">click</span> of <span class="term"><a href="x">click</a></span><br />
+  *  <em>element content</em> -  content between the opening and closing tags of an element, like <span class="term">click</span> of the <span class="term"><a href="x">click</a></span> element<br />
  *  <em>HTML</em> - implies XHTML unless specified otherwise<br />
-  *  <em>input</em> - text string given to htmLawed to process<br />
+  *  <em>HTML body</em> - Complete HTML documents typically have a <em>head</em> and a <em>body</em> container. Information in <em>head</em> specifies title of the document, etc., whereas that in the body informs what is to be displayed on a web-page; it is only the elements for <em>body</em>, except <span class="term">frames</span>, <span class="term">frameset</span> and <span class="term">noframes</span> that htmLawed is concerned with<br />
+  *  <em>input</em> - text given to htmLawed to process<br />
  *  <em>processing</em> - involves filtering, correction, etc., of input<br />
-  *  <em>safe</em> - absence or reduction of certain characters and HTML elements and attributes in the input that can otherwise potentially and circumstantially expose web-site users to security vulnerabilities like cross-site scripting attacks (XSS)<br />
-  *  <em>scheme</em> - URL protocol like <span class="term">http</span> and <span class="term">ftp</span><br />
-  *  <em>specs</em> - standard specifications<br />
+  *  <em>safe</em> - absence or reduction of certain characters and HTML elements and attributes in HTML of text that can otherwise potentially, and circumstantially, expose text readers to security vulnerabilities like cross-site scripting attacks (XSS)<br />
+  *  <em>scheme</em> - a URL protocol like <span class="term">http</span> and <span class="term">ftp</span><br />
+  *  <em>specifications</em> - standard specifications, for HTML4, HTML5, Ruby, etc.<br />
  *  <em>style property</em> - terms like <span class="term">border</span> and <span class="term">height</span> for which declarations are made in values for the <span class="term">style</span> attribute of elements<br />
  *  <em>tag</em> - markers like <span class="term"><a href="x"></span> and <span class="term"></a></span> delineating element content; the opening tag can contain attributes<br />
  *  <em>tag content</em> - consists of tag markers <span class="term"><</span> and <span class="term">></span>, element names like <span class="term">div</span>, and possibly attributes<br />
  *  <em>user</em> - administrator<br />
  *  <em>writer</em> - end-user like a blog commenter providing the input that is to be processed; also, <em>author</em><br />
+</div>
+<div class="sub-section"><h3>
+<a name="s1.6" id="s1.6"></a><span class="item-no">1.6</span>  Availability
+</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
+<br />
+  htmLawed can be downloaded for free at its <a href="http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed">website</a>. Besides the <span class="term">htmLawed.php</span> file, the download has the htmLawed documentation (this document) in plain <a href="htmLawed_README.txt">text</a> and <a href="htmLawed_README.htm">HTML</a> formats, a script for <a href="htmLawedTest.php">testing</a>, and a text file for <a href="htmLawed_TESTCASE.txt">test-cases</a>. htmLawed is also available as a PHP class (OOP code) on its website.<br />
+
</div>
</div>
<div class="section"><h2>
<a name="s2" id="s2"></a><span class="item-no">2</span>  Usage
</h2><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed should work with PHP 4.3 and higher. Either <span class="term">include()</span> the <span class="term">htmLawed.php</span> file or copy-paste the entire code.<br />
+  htmLawed works in PHP version 4.4 or higher. Either <span class="term">include()</span> the <span class="term">htmLawed.php</span> file, or copy-paste the entire code. To use with PHP 4.3, have the following code included:<br />
+<br />
+
+<code class="code">    if(!function_exists('ctype_digit')){</code>
+<br />
+
+<code class="code">     function ctype_digit($var){</code>
+<br />
+
+<code class="code">      return ((int) $var == $var);</code>
+<br />
+
+<code class="code">     }</code>
+<br />
+
+<code class="code">    }</code>
<br />
-  To easily <strong>test</strong> htmLawed using a form-based interface, use the provided <a href="htmLawedTest.php">demo</a> (<span class="term">htmLawed.php</span> and <span class="term">htmLawedTest.php</span> should be in the same directory on the web-server).<br />
<div class="sub-section"><h3>
<a name="s2.1" id="s2.1"></a><span class="item-no">2.1</span>  Simple
<code class="code">    $processed = htmLawed($text);</code>
<br />
<br />
-  <strong>Note</strong>: If input is from a <span class="term">$_GET</span> or <span class="term">$_POST</span> value, and <span class="term">magic quotes</span> are enabled on the PHP setup, run <span class="term">stripslashes()</span> on the input before passing to htmLawed.<br />
+  With the <span class="term">htmLawed class</span> (<a href="#s1.6">section 1.6</a>), usage is:<br />
+<br />
+
+<code class="code">    $processed = htmLawed::hl($text);</code>
+<br />
+<br />
+  <strong>Notes</strong>: (1) If input is from a <span class="term">$_GET</span> or <span class="term">$_POST</span> value, and <span class="term">magic quotes</span> are enabled on the PHP setup, run <span class="term">stripslashes()</span> on the input before passing to htmLawed. (2) htmLawed does not have support for head-level elements, <span class="term">body</span>, and the frame-level elements, <span class="term">frameset</span>, <span class="term">frame</span> and <span class="term">noframes</span>.<br />
<br />
  By default, htmLawed will process the text allowing all valid HTML elements/tags, secure URL scheme/CSS style properties, etc. It will allow <span class="term">CDATA</span> sections and HTML comments, balance tags, and ensure proper nesting of elements. Such actions can be configured using two other optional arguments -- <span class="term">$config</span> and <span class="term">$spec</span>:<br />
<br />
<code class="code">    $processed = htmLawed($text, $config, $spec);</code>
<br />
<br />
-  These extra parameters are detailed below. Some examples are shown in <a href="#s2.9">section 2.9</a>.<br />
-<br />
-  <strong>Note</strong>: For maximum protection against <span class="term">XSS</span> and other scripting attacks (e.g., by disallowing Javascript code), consider using the <span class="term">safe</span> parameter; see <a href="#s3.6">section 3.6</a>.<br />
+  The <span class="term">$config</span> and <span class="term">$spec</span> arguments are detailed below. Some examples are shown in <a href="#s2.9">section 2.9</a>. For maximum protection against <span class="term">XSS</span> and other scripting attacks (e.g., by disallowing Javascript code), consider using the <span class="term">safe</span> parameter; see <a href="#s3.6">section 3.6</a>.<br />
</div>
<div class="sub-section"><h3>
  Anti-link-spam measure; see <a href="#s3.4.7">section 3.4.7</a><br />
<br />
  <span class="term">0</span> - no measure taken  *<br />
-  <
span class="term">array("regex1", "regex2")</span> - will ensure a <span class="term">rel</span> attribute with <span class="term">nofollow</span> in its value in case the <span class="term">href</span> attribute value matches the regular expression pattern <span class="term">regex1</span>, and/or will remove <span class="term">href</span> if its value matches the regular expression pattern <span class="term">regex2</span>. E.g., <span class="term">array("/./", "/://\W*(?!(abc\.com|xyz\.org))/")</span>; see <a href="#s3.4.7">section 3.4.7</a> for more.<br />
+  <
em>array("regex1", "regex2")</em> - will ensure a <span class="term">rel</span> attribute with <span class="term">nofollow</span> in its value in case the <span class="term">href</span> attribute value matches the regular expression pattern <span class="term">regex1</span>, and/or will remove <span class="term">href</span> if its value matches the regular expression pattern <span class="term">regex2</span>. E.g., <span class="term">array("/./", "/://\W*(?!(abc\.com|xyz\.org))/")</span>; see <a href="#s3.4.7">section 3.4.7</a> for more.<br />
<br />
  <strong>anti_mail_spam</strong><br />
  Anti-mail-spam measure; see <a href="#s3.4.7">section 3.4.7</a><br />
<br />
  <span class="term">0</span> - no measure taken  *<br />
-  <span class="term">word</span> - <span class="term">@</span> in mail address in <span class="term">href</span> attribute value is replaced with specified <span class="term">word</span><br />
+  <em>word</em> - <span class="term">@</span> in mail address in <span class="term">href</span> attribute value is replaced with specified <em>word</em><br />
<br />
  <strong>balance</strong><br />
  Balance tags for well-formedness and proper nesting; see <a href="#s3.3.3">section 3.3.3</a><br />
  Denied HTML attributes; see <a href="#s3.4">section 3.4</a><br />
<br />
  <span class="term">0</span> - none  *<br />
-  <span class="term">string</span> - dictated by values in <span class="term">string</span><br />
+  <em>string</em> - dictated by values in <em>string</em><br />
  <span class="term">on*</span> (like <span class="term">onfocus</span>) attributes not allowed - "<br />
<br />
+  <strong>direct_nest_list</strong><br />
+  Allow direct nesting of a list within another without requiring it to be a list item; see <a href="#s3.3.4">section 3.3.4</a><br />
+<br />
+  <span class="term">0</span> - no  *<br />
+  <span class="term">1</span> - yes<br />
+<br />
  <strong>elements</strong><br />
  Allowed HTML elements; see <a href="#s3.3">section 3.3</a><br />
<br />
  Name of an optional hook function to alter the input string, <span class="term">$config</span> or <span class="term">$spec</span> before htmLawed starts its main work; see <a href="#s3.7">section 3.7</a><br />
<br />
  <span class="term">0</span> - no hook function  *<br />
-  <span class="term">name</span> - <span class="term">name</span> is name of the hook function (<span class="term">kses_hook</span>  ^)<br />
+  <em>name</em> - <em>name</em> is name of the hook function (<span class="term">kses_hook</span>  ^)<br />
<br />
  <strong>hook_tag</strong><br />
  Name of an optional hook function to alter tag content finalized by htmLawed; see <a href="#s3.4.9">section 3.4.9</a><br />
<br />
  <span class="term">0</span> - no hook function  *<br />
-  <span class="term">name</span> - <span class="term">name</span> is name of the hook function<br />
+  <em>name</em> - <em>name</em> is name of the hook function<br />
<br />
  <strong>keep_bad</strong><br />
  Neutralize bad tags by converting <span class="term"><</span> and <span class="term">></span> to entities, or remove them; see <a href="#s3.3.3">section 3.3.3</a><br />
  <span class="term">1</span> - will auto-adjust other relevant <span class="term">$config</span> parameters (indicated by <span class="term">"</span> in this list)<br />
<br />
  <strong>schemes</strong><br />
-  Array of attribute-specific, comma-separated, lower-cased list of schemes (protocols) allowed in attributes accepting URLs; <span class="term">*</span> covers all unspecified attributes; see <a href="#s3.4.3">section 3.4.3</a><br />
+  Array of attribute-specific, comma-separated, lower-cased list of schemes (protocols) allowed in attributes accepting URLs
(or <span class="term">!</span> to <em>deny</em> any URL); <span class="term">*</span> covers all unspecified attributes; see <a href="#s3.4.3">section 3.4.3</a><br />
<br />
  <span class="term">href: aim, feed, file, ftp, gopher, http, https, irc, mailto, news, nntp, sftp, ssh, telnet; *:file, http, https</span>  *<br />
  <span class="term">*: ftp, gopher, http, https, mailto, news, nntp, telnet</span>  ^<br />
-  <span class="term">href: aim, feed, file, ftp, gopher, http, https, irc, mailto, news, nntp, sftp, ssh, telnet; style: nil; *:file, http, https</span>  "<br />
+  <span class="term">href: aim, feed, file, ftp, gopher, http, https, irc, mailto, news, nntp, sftp, ssh, telnet; style: !; *:file, http, https</span>  "<br />
<br />
  <strong>show_setting</strong><br />
  Name of a PHP variable to assign the <em>finalized</em> <span class="term">$config</span> and <span class="term">$spec</span> values; see <a href="#s3.8">section 3.8</a><br />
<br />
  <span class="term">0</span> - no  ^<br />
  <span class="term">1</span> - remove duplicate and/or invalid ones  *<br />
-  <span class="term">word</span> - remove invalid ones and replace duplicate ones with new and unique ones based on the <span class="term">word</span>; the admin-specified <span class="term">word</span>, like <span class="term">my_</span>, should begin with a letter (a-z) and can contain letters, digits, <span class="term">.</span>, <span class="term">_</span>, <span class="term">-</span>, and <span class="term">:</span>.<br />
+  <em>word</em> - remove invalid ones and replace duplicate ones with new and unique ones based on the <em>word</em>; the admin-specified <em>word</em>, like <span class="term">my_</span>, should begin with a letter (a-z) and can contain letters, digits, <span class="term">.</span>, <span class="term">_</span>, <span class="term">-</span>, and <span class="term">:</span>.<br />
<br />
  <strong>valid_xhtml</strong><br />
  Magic parameter to make input the most valid XHTML without needing to specify other relevant <span class="term">$config</span> parameters; see <a href="#s3.5">section 3.5</a><br />
<a name="s2.3" id="s2.3"></a><span class="item-no">2.3</span>  Extra HTML specifications using the $spec parameter
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  The <span class="term">$spec</span> argument can be used to disallow an otherwise legal attribute for an element, or to restrict the attribute's values. This can also be helpful as a security measure (e.g., in certain versions of browsers, certain values can cause buffer overflows and denial of service attacks), or in enforcing admin policy compliance. <span class="term">$spec</span> is specified as a string of text containing one or more <em>rules</em>, with multiple rules separated from each other by a semi-colon (<span class="term">;</span>). E.g.,<br />
+  The <span class="term">$spec</span> argument of htmLawed can be used to disallow an otherwise legal attribute for an element, or to restrict the attribute's values. This can also be helpful as a security measure (e.g., in certain versions of browsers, certain values can cause buffer overflows and denial of service attacks), or in enforcing admin policies. <span class="term">$spec</span> is specified as a string of text containing one or more <em>rules</em>, with multiple rules separated from each other by a semi-colon (<span class="term">;</span>). E.g.,<br />
<br />
<code class="code">    $spec = 'i=-*; td, tr=style, id, -*; a=id(match="/[a-z][a-z\d.:\-`"]*/i"/minval=2), href(maxlen=100/minlen=34); img=-width,-alt';</code>
  *  <span class="term">a=-*, href, title</span> - none except <span class="term">href</span> and <span class="term">title</span><br />
  *  <span class="term">a=-*, -id, href, title</span> - none except <span class="term">href</span> and <span class="term">title</span><br />
<br />
-  Rules regarding <strong>attribute values</strong> are optionally specified inside round brackets after attribute names in slash ('/')-separated <em>parameter = value</em> pairs. E.g., <span class="term">title(maxlen=30/minlen=5)</span>. None, or one or more of the following parameters may be specified:<br />
+  Rules regarding <strong>attribute values</strong> are optionally specified inside round brackets after attribute names in slash ('/')-separated <em>parameter = value</em> pairs. E.g., <span class="term">title(maxlen=30/minlen=5)</span>. None or one or more of the following parameters may be specified:<br />
<br />
  *  <span class="term">oneof</span> - one or more choices separated by <span class="term">|</span> that the value should match; if only one choice is provided, then the value must match that choice<br />
<br />
  <em>Rule</em>: <span class="term">input=title(), value(maxval=8/default=6)</span><br />
  <em>Output</em>: <span class="term"><input title="WIDTH" value="6" /><input title="length" value="5" /></span><br />
<br />
-  <em>Rule</em>: <span class="term">input=title(nomatch=$w.d$i), value(match=$em$/default=6em)</span><br />
+  <em>Rule</em>: <span class="term">input=title(nomatch=%w.d%i), value(match=%em%/default=6em)</span><br />
  <em>Output</em>: <span class="term"><input value="10em" /><input title="length" value="6em" /></span><br />
<br />
  <em>Rule</em>: <span class="term">input=title(oneof=height|depth/default=depth), value(noneof=5|6)</span><br />
<br />
  <strong>Special characters</strong>: The characters <span class="term">;</span>, <span class="term">,</span>, <span class="term">/</span>, <span class="term">(</span>, <span class="term">)</span>, <span class="term">|</span>, <span class="term">~</span> and space have special meanings in the rules. Words in the rules that use such characters, or the characters themselves, should be <em>escaped</em> by enclosing in pairs of double-quotes (<span class="term">"</span>). A back-tick (<span class="term">`</span>) can be used to escape a literal <span class="term">"</span>. An example rule illustrating this is <span class="term">input=value(maxlen=30/match="/^\w/"/default="your `"ID`"")</span>.<br />
<br />
-  <strong>Note</strong>: To deny an attribute for all elements for which it is legal, <span class="term">$config["deny_attribute"]</span> (see <a href="#s3.4">section 3.4</a>) can be used instead of <span class="term">$spec</span>. Also, attributes can be allowed element-specifically through <span class="term">$spec</span> while being denied globally through <span class="term">$config["deny_attribute"]</span>. The <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) can also be used to implement the <span class="term">$spec</span> functionality.<br />
+  <strong>Note</strong>: To deny an attribute for all elements for which it is legal, <span class="term">$config["deny_attribute"]</span> (see <a href="#s3.4">section 3.4</a>) can be used instead of <span class="term">$spec</span>. Also, attributes can be allowed element-specifically through <span class="term">$spec</span> while being denied globally through <span class="term">$config["deny_attribute"]</span>. The <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) can also be possibly used to implement a functionality like that achieved using <span class="term">$spec</span> functionality.<br />
+<br />
+  <span class="term">$spec</span> can also be used to permit custom, non-standard attributes as well as custom rules for standard attributes. Thus, the following value of <span class="term">$spec</span> will permit the custom uses of the standard <span class="term">rel</span> attribute in <span class="term">input</span> (not permitted as per standards) and of a non-standard attribute, <span class="term">vFlag</span>, in <span class="term">img</span>.<br />
+<br />
+
+<code class="code">    $spec = 'img=vFlag; input=rel'</code>
+<br />
+<br />
+  The attribute names can contain alphabets, colons (:) and hyphens (-), but they must start with an alphabet.<br />
</div>
<div class="sub-section"><h3>
<a name="s2.4" id="s2.4"></a><span class="item-no">2.4</span>  Performance time & memory usage
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  The time and memory used by htmLawed depends on its configuration and the size of the input, and the amount, nestedness and well-formedness of the HTML markup within it. In particular, tag balancing and beautification each can increase the processing time by about a quarter.<br />
+  The time and memory consumed during text processing by htmLawed depends on its configuration, the size of the input, and the amount, nestedness and well-formedness of the HTML markup within the input. In particular, tag balancing and beautification each can increase the processing time by about a quarter.<br />
<br />
  The htmLawed <a href="htmLawedTest.php">demo</a> can be used to evaluate the performance and effects of different types of input and <span class="term">$config</span>.<br />
<a name="s2.5" id="s2.5"></a><span class="item-no">2.5</span>  Some security risks to keep in mind
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  When setting the parameters/arguments (like those to allow certain HTML elements) for use with htmLawed, one should bear in mind that the setting may let through potentially <em>dangerous</em> HTML code. (This may not be a problem if the authors are trusted.)<br />
-<br />
-  For example, following increase security risks:<br />
+  When setting the parameters/arguments (like those to allow certain HTML elements) for use with htmLawed, one should bear in mind that the setting may let through potentially <em>dangerous</em> HTML code which is meant to steal user-data, deface a website, render a page non-functional, etc. Unless end-users, either people or software, supplying the content are completely trusted, security issues arising from the degree of HTML usage permitted through htmLawed's setting should be considered. For example, following increase security risks:<br />
<br />
  *  Allowing <span class="term">script</span>, <span class="term">applet</span>, <span class="term">embed</span>, <span class="term">iframe</span> or <span class="term">object</span> elements, or certain of their attributes like <span class="term">allowscriptaccess</span><br />
<br />
  *  Allowing HTML comments (some Internet Explorer versions are vulnerable with, e.g., <span class="term"><!--[if gte IE 4]><script>alert("xss");</script><![endif]--></span><br />
<br />
-  *  Allowing dynamic CSS expressions (a feature of the IE browser)<br />
+  *  Allowing dynamic CSS expressions (some Internet Explorer versions are vulnerable)<br />
+<br />
+  *  Allowing the <span class="term">style</span> attribute<br />
+<br />
+  To remove <em>unsecure</em> HTML, code-developers using htmLawed must set <span class="term">$config</span> appropriately. E.g., <span class="term">$config["elements"] = "* -script"</span> to deny the <span class="term">script</span> element (<a href="#s3.3">section 3.3</a>), <span class="term">$config["safe"] = 1</span> to auto-configure ceratin htmLawed parameters for maximizing security (<a href="#s3.6">section 3.6</a>), etc.<br />
<br />
-  <em>Unsafe</em> HTML can be removed by setting <span class="term">$config</span> appropriately. E.g., <span class="term">$config["elements"] = "* -script"</span> (<a href="#s3.3">section 3.3</a>), <span class="term">$config["safe"] = 1</span> (<a href="#s3.6">section 3.6</a>), etc.<br />
+  Permitting the <span class="term">*style*</span> attribute brings in risks of <em>click-jacking</em>, <em>phishing</em>, web-page overlays, etc., <em>even</em> when the <span class="term">safe</span> parameter is enabled (see <a href="#s3.6">section 3.6</a>). Except for URLs and a few other things like CSS dynamic expressions, htmLawed currently does not check every CSS style property. It does provide ways for the code-developer implementing htmLawed to do such checks through htmLawed's <span class="term">$spec</span> argument, and through the <span class="term">hook_tag</span> parameter (see <a href="#s3.4.8">section 3.4.8</a> for more). Disallowing <span class="term">style</span> completely and relying on CSS classes and stylesheet files is recommended.<br />
+<br />
+  htmLawed does not check or correct the character <strong>encoding</strong> of the input it receives. In conjunction with permissive circumstances, such as when the character encoding is left undefined through HTTP headers or HTML <span class="term">meta</span> tags, this can allow for an exploit (like Google's <em>UTF-7/XSS</em> vulnerability of the past).<br />
</div>
<div class="sub-section"><h3>
<a name="s2.7" id="s2.7"></a><span class="item-no">2.7</span>  Tolerance for ill-written HTML
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed can work with ill-written HTML code in the input. However, HTML that is too ill-written may not be <em>read</em> as HTML, and be considered mere plain text instead. Following statements indicate the degree of <em>looseness</em> that htmLawed can work with, and can be provided in instructions to writers:<br />
+  htmLawed can work with ill-written HTML code in the input. However, HTML that is too ill-written may not be <em>read</em> as HTML, and may therefore get identified as mere plain text. Following statements indicate the degree of <em>looseness</em> that htmLawed can work with, and can be provided in instructions to writers:<br />
<br />
  *  Tags must be flanked by <span class="term"><</span> and <span class="term">></span> with no <span class="term">></span> inside -- any needed <span class="term">></span> should be put in as <span class="term">&gt;</span>. It is possible for tag content (element name and attributes) to be spread over many lines instead of being on one. A space may be present between the tag content and <span class="term">></span>, like <span class="term"><div ></span> and <span class="term"><img / ></span>, but not after the <span class="term"><</span>.<br />
<br />
<br />
  *  Attribute string of elements may be liberally spaced with tabs, line-breaks, etc.<br />
<br />
-  *  Attribute values may not be double-quoted, or may be single-quoted.<br />
+  *  Attribute values may be single- and not double-quoted.<br />
<br />
  *  Left-padding of numeric entities (like, <span class="term">&#0160;</span>, <span class="term">&x07ff;</span>) with <span class="term">0</span> is okay as long as the number of characters between between the <span class="term">&</span> and the <span class="term">;</span> does not exceed 8. All entities must end with <span class="term">;</span> though.<br />
<br />
-  *  Named character entities must be properly cased. E.g., <span class="term">&Lt;</span> or <span class="term">&TILDE;</span> will not be let through without modification.<br />
+  *  Named character entities must be properly cased. Thus, <span class="term">&Lt;</span> or <span class="term">&TILDE;</span> will not be recognized as entities and will be <em>neutralized</em>.<br />
<br />
-  *  HTML comments should not be inside element tags (okay between tags), and should begin with <span class="term"><!--</span> and end with <span class="term">--></span>. Characters like <span class="term"><</span>, <span class="term">></span>, and <span class="term">&</span> may be allowed inside depending on <span class="term">$config</span>, but any <span class="term">--></span> inside should be put in as <span class="term">--&gt;</span>. Any <span class="term">--</span> inside will be automatically converted to <span class="term">-</span>, and a space will be added before the comment delimiter <span class="term">--></span>.<br />
+  *  HTML comments should not be inside element tags (they can be between tags), and should begin with <span class="term"><!--</span> and end with <span class="term">--></span>. Characters like <span class="term"><</span>, <span class="term">></span>, and <span class="term">&</span> may be allowed inside depending on <span class="term">$config</span>, but any <span class="term">--></span> inside should be put in as <span class="term">--&gt;</span>. Any <span class="term">--</span> inside will be automatically converted to <span class="term">-</span>, and a space will be added before the comment delimiter <span class="term">--></span>.<br />
<br />
  *  <span class="term">CDATA</span> sections should not be inside element tags, and can be in element content only if plain text is allowed for that element. They should begin with <span class="term"><[CDATA[</span> and end with <span class="term">]]></span>. Characters like <span class="term"><</span>, <span class="term">></span>, and <span class="term">&</span> may be allowed inside depending on <span class="term">$config</span>, but any <span class="term">]]></span> inside should be put in as <span class="term">]]&gt;</span>.<br />
<br />
  *  With <span class="term">$config["unique_ids"]</span> not <span class="term">0</span> and the <span class="term">id</span> attribute being permitted, writers should carefully avoid using duplicate or invalid <span class="term">id</span> values as even though htmLawed will correct/remove the values, the final output may not be the one desired. E.g., when <span class="term"><a id="home"></a><input id="home" /><label for="home"></label></span> is processed into<br />
<span class="term"><a id="home"></a><input id="prefix_home" /><label for="home"></label></span>.<br />
<br />
-  *  Note that even if intended HTML is lost in a highly ill-written input, the processed output will be more secure and standard-compliant.<br />
+  *  Even if intended HTML is lost from an ill-written input, the processed output will be more secure and standard-compliant.<br />
<br />
  *  For URLs, unless <span class="term">$config["scheme"]</span> is appropriately set, writers should avoid using escape characters or entities in schemes. E.g., <span class="term">htt&#112;</span> (which many browsers will read as the harmless <span class="term">http</span>) may be considered bad by htmLawed.<br />
<br />
-  *  htmLawed will attempt to put plain text present directly inside <span class="term">blockquote</span>, <span class="term">form</span>, <span class="term">map</span> and <span class="term">noscript</span> elements (illegal as per the specs) inside auto-generated <span class="term">div</span> elements.<br />
+  *  htmLawed will attempt to put plain text present directly inside <span class="term">blockquote</span>, <span class="term">form</span>, <span class="term">map</span> and <span class="term">noscript</span> elements (illegal as per the specifications) inside auto-generated <span class="term">div</span> elements.<br />
</div>
<div class="sub-section"><h3>
<a name="s2.8" id="s2.8"></a><span class="item-no">2.8</span>  Limitations & work-arounds
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed's main objective is to make the input text <em>more</em> standard-compliant, secure for web-page readers, and free of HTML elements and attributes considered undesirable by the administrator. Some of its current limitations, regardless of this objective, are noted below along with work-arounds.<br />
+  htmLawed's main objective is to make the input text <em>more</em> standard-compliant, secure for readers, and free of HTML elements and attributes considered undesirable by the administrator. Some of its current limitations, regardless of this objective, are noted below along with work-arounds.<br />
<br />
-  It should be borne in mind that no browser application is 100% standard-compliant, and that some of the standard specs (like asking for normalization of white-spacing within <span class="term">textarea</span> elements) are clearly wrong. Regarding security, note that <em>unsafe</em> HTML code is not necessarily legally invalid.<br />
+  It should be borne in mind that no browser application is 100% standard-compliant, and that some of the standard specifications (like asking for normalization of white-spacing within <span class="term">textarea</span> elements) are clearly wrong. Regarding security, note that <em>unsafe</em> HTML code is not legally invalid per se.<br />
<br />
-  *  htmLawed is meant for input that goes into the <span class="term">body</span> of HTML documents. HTML's head-level elements are not supported, nor are the frameset elements <span class="term">frameset</span>, <span class="term">frame</span> and <span class="term">noframes</span>.<br />
+  *  htmLawed is meant for input that goes into the <span class="term">body</span> of HTML documents. HTML's head-level elements are not supported, nor are the frameset elements <span class="term">frameset</span>, <span class="term">frame</span> and <span class="term">noframes</span>. Content of the latter elements can, however, be individually filtered through htmLawed.<br />
<br />
  *  It cannot transform the non-standard <span class="term">embed</span> elements to the standard-compliant <span class="term">object</span> elements. Yet, it can allow <span class="term">embed</span> elements if permitted (<span class="term">embed</span> is widely used and supported). Admins can certainly use the <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) to deploy a custom embed-to-object converter function.<br />
<br />
<br />
  *  By default, htmLawed won't check many attribute values for standard compliance. E.g., <span class="term">width="20m"</span> with the dimension in non-standard <span class="term">m</span> is let through. Implementing universal and strict attribute value checks can make htmLawed slow and resource-intensive. Admins should look at the <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) or <span class="term">$spec</span> to enforce finer checks.<br />
<br />
-  *  The attributes, deprecated (which can be transformed too) or not, that it supports are largely those that are in the specs. Only a few of the proprietary attributes are supported.<br />
+  *  The attributes, deprecated (which can be transformed too) or not, that it supports are largely those that are in the specifications. Only a few of the proprietary attributes are supported.<br />
<br />
  *  Except for contained URLs and dynamic expressions (also optional), htmLawed does not check CSS style property values. Admins should look at using the <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) or <span class="term">$spec</span> for finer checks. Perhaps the best option is to disallow <span class="term">style</span> but allow <span class="term">class</span> attributes with the right <span class="term">oneof</span> or <span class="term">match</span> values for <span class="term">class</span>, and have the various class style properties in <span class="term">.css</span> CSS stylesheet files.<br />
<br />
<br />
  *  Except for optionally converting absolute or relative URLs to the other type, htmLawed will not alter URLs (e.g., to change the value of query strings or to convert <span class="term">http</span> to <span class="term">https</span>. Having absolute URLs may be a standard-requirement, e.g., when HTML is embedded in email messages, whereas altering URLs for other purposes is beyond htmLawed's goals. Admins may be able to use a custom hook function to enforce such checks (<span class="term">hook_tag</span> parameter; see <a href="#s3.4.9">section 3.4.9</a>).<br />
<br />
-  *  Pairs of opening and closing tags that do not enclose any content (like <span class="term"><em></em></span>) are not removed. This may be against the standard specs for certain elements (e.g., <span class="term">table</span>). However, presence of such standard-incompliant code will not break the display or layout of content. Admins can also use simple regex-based code to filter out such code.<br />
+  *  Pairs of opening and closing tags that do not enclose any content (like <span class="term"><em></em></span>) are not removed. This may be against the standard specifications for certain elements (e.g., <span class="term">table</span>). However, presence of such standard-incompliant code will not break the display or layout of content. Admins can also use simple regex-based code to filter out such code.<br />
<br />
-  *  htmLawed does not check for certain element orderings described in the standard specs (e.g., in a <span class="term">table</span>, <span class="term">tbody</span> is allowed before <span class="term">tfoot</span>). Admins may be able to use a custom hook function to enforce such checks (<span class="term">hook_tag</span> parameter; see <a href="#s3.4.9">section 3.4.9</a>).<br />
+  *  htmLawed does not check for certain element orderings described in the standard spec
ifications (e.g., in a <span class="term">table</span>, <span class="term">tbody</span> is allowed before <span class="term">tfoot</span>). Admins may be able to use a custom hook function to enforce such checks (<span class="term">hook_tag</span> parameter; see <a href="#s3.4.9">section 3.4.9</a>).<br />
<br />
-  *  htmLawed does not check the number of nested elements. E.g., it will allow two <span class="term">caption</span> elements in a <span class="term">table</span> element, illegal as per the specs. Admins may be able to use a custom hook function to enforce such checks (<span class="term">hook_tag</span> parameter; see <a href="#s3.4.9">section 3.4.9</a>).<br />
+  *  htmLawed does not check the number of nested elements. E.g., it will allow two <span class="term">caption</span> elements in a <span class="term">table</span> element, illegal as per the spec
ifications. Admins may be able to use a custom hook function to enforce such checks (<span class="term">hook_tag</span> parameter; see <a href="#s3.4.9">section 3.4.9</a>).<br />
<br />
  *  htmLawed might convert certain entities to actual characters and remove backslashes and CSS comment-markers (<span class="term">/*</span>) in <span class="term">style</span> attribute values in order to detect malicious HTML like crafted IE-specific dynamic expressions like <span class="term">&#101;xpression...</span>. If this is too harsh, admins can allow CSS expressions through htmLawed core but then use a custom function through the <span class="term">hook_tag</span> parameter (<a href="#s3.4.9">section 3.4.9</a>) to more specifically identify CSS expressions in the <span class="term">style</span> attribute values. Also, using <span class="term">$config["style_pass"]</span>, it is possible to have htmLawed pass <span class="term">style</span> attribute values without even looking at them (<a href="#s3.4.8">section 3.4.8</a>).<br />
<br />
<br />
  *  Because of poor Unicode support in PHP, htmLawed does not remove the <em>high value</em> HTML-invalid characters with multi-byte code-points. Such characters however are extremely unlikely to be in the input. (see <a href="#s3.1">section 3.1</a>).<br />
<br />
+  *  htmLawed does not check or correct the character encoding of the input it receives. In conjunction with permitting circumstances such as when the character encoding is left undefined through HTTP headers or HTML <span class="term">meta</span> tags, this can permit an exploit (like Google's <em>UTF-7/XSS</em> vulnerability of the past). Also, htmLawed can mangle input text if it is not well-formed in terms of character encoding. Administrators can consider using code available elsewhere to check well-formedness of input text characters to correct any defect.<br />
+<br />
+  *  htmLawed is expected to work with input texts in ASCII-compatible single byte encodings such as national variants of ASCII (like ISO-646-DE/German of the ISO 646 standard), extended ASCII variants (like ISO 8859-10/Turkish of the ISO 8859/ISO Latin standard), ISO 8859-based Windows variants (like Windows 1252), EBCDIC, Shift JIS (Japanese), GB-Roman (Chinese), and KS-Roman (Korean). It should also properly handle texts with variable byte encodings like UTF-7 (Unicode) and UTF-8 (Unicode). However, htmLawed may mangle input texts with double byte encodings like UTF-16 (Unicode), JIS X 0208:1997 (Japanese) and K SX 1001:1992 (Korean), or the UTF-32 (Unicode) quadruple byte encoding. If an input text has such an encoding, administrators can use PHP's <a href="http://php.net/manual/en/book.iconv.php">iconv</a> functions, or some other mean, to convert text to UTF-8 before passing it to htmLawed.<br />
+<br />
  *  Like any script using PHP's PCRE regex functions, PHP setup-specific low PCRE limit values can cause htmLawed to at least partially fail with very long input texts.<br />
</div>
<div class="sub-section"><h3>
-<a name="s2.9" id="s2.9"></a><span class="item-no">2.9</span>  Examples
+<a name="s2.9" id="s2.9"></a><span class="item-no">2.9</span>  Examples of usage
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  <strong>1.</strong> A blog administrator wants to allow only <span class="term">a</span>, <span class="term">em</span>, <span class="term">strike</span>, <span class="term">strong</span> and <span class="term">u</span> in comments, but needs <span class="term">strike</span> and <span class="term">u</span> transformed to <span class="term">span</span> for better XHTML 1-strict compliance, and, he wants the <span class="term">a</span> links to be to <span class="term">http</span> or <span class="term">https</span> resources:<br />
+  Safest, allowing only <em>safe</em> HTML markup --<br />
+<br />
+
+<code class="code">    $config = array('safe'=>1);</code>
+<br />
+
+<code class="code">    $out = htmLawed($in);</code>
+<br />
+<br />
+  Simplest, allowing all valid HTML markup except <span class="term">javascript:</span> --<br />
+<br />
+
+<code class="code">    $out = htmLawed($in);</code>
+<br />
+<br />
+  Allowing all valid HTML markup including <span class="term">javascript:</span> --<br />
+<br />
+
+<code class="code">    $config = array('schemes'=>'*:*');</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Allowing only <span class="term">safe</span> HTML and the elements <span class="term">a</span>, <span class="term">em</span>, and <span class="term">strong</span> --<br />
+<br />
+
+<code class="code">    $config = array('safe'=>1, 'elements'=>'a, em, strong');</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Not allowing elements <span class="term">script</span> and <span class="term">object</span> --<br />
+<br />
+
+<code class="code">    $config = array('elements'=>'* -script -object');</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Not allowing attributes <span class="term">id</span> and <span class="term">style</span> --<br />
+<br />
+
+<code class="code">    $config = array('deny_attribute'=>'id, style');</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Permitting only attributes <span class="term">title</span> and <span class="term">href</span> --<br />
+<br />
+
+<code class="code">    $config = array('deny_attribute'=>'* -title -href');</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Remove bad/disallowed tags altogether instead of converting them to entities --<br />
+<br />
+
+<code class="code">    $config = array('keep_bad'=>0);</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config);</code>
+<br />
+<br />
+  Allowing attribute <span class="term">title</span> only in <span class="term">a</span> and not allowing attributes <span class="term">id</span>, <span class="term">style</span>, or scriptable <em>on*</em> attributes like <span class="term">onclick</span> --<br />
+<br />
+
+<code class="code">    $config = array('deny_attribute'=>'title, id, style, on*');</code>
+<br />
+
+<code class="code">    $spec = 'a=title';</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config, $spec);</code>
+<br />
+<br />
+  Allowing a custom attribute, <span class="term">vFlag</span>, in <span class="term">img</span> and permitting custom use of the standard attribute, <span class="term">rel</span>, in <span class="term">input</span> --<br />
+<br />
+
+<code class="code">    $spec = 'img=vFlag; input=rel';</code>
+<br />
+
+<code class="code">    $out = htmLawed($in, $config, $spec);</code>
+<br />
+<br />
+  Some case-studies are presented below.<br />
+<br />
+  <strong>1.</strong> A blog administrator wants to allow only <span class="term">a</span>, <span class="term">em</span>, <span class="term">strike</span>, <span class="term">strong</span> and <span class="term">u</span> in comments, but needs <span class="term">strike</span> and <span class="term">u</span> transformed to <span class="term">span</span> for better XHTML 1-strict compliance, and, he wants the <span class="term">a</span> links to point only to <span class="term">http</span> or <span class="term">https</span> resources:<br />
<br />
<code class="code">    $processed = htmLawed($in, array('elements'=>'a, em, strike, strong, u', 'make_tag_strict'=>1, 'safe'=>1, 'schemes'=>'*:http, https'), 'a=href');</code>
<br />
  The character values are replaced with entities/characters and not character values referred to by the entities/characters to keep this task independent of the character-encoding of input text.<br />
<br />
-  The <span class="term">$config["clean_ms_char"]</span> parameter need not be used if authors do not copy-paste Microsoft-created text or if the input text is not believed to use the <span class="term">Windows 1252</span> or a similar encoding. Further, the input form and the web-pages displaying it or its content should have the character encoding appropriately marked-up.<br />
+  The <span class="term">$config["clean_ms_char"]</span> parameter should not be used if authors do not copy-paste Microsoft-created text, or if the input text is not believed to use the <span class="term">Windows 1252</span> (<span class="term">Cp-1252</span>) or a similar encoding like <span class="term">Cp-1251</span> (otherwise, for example when UTF-8 encoding is in use, Japanese or Korean characters can get mangled). Further, the input form and the web-pages displaying it or its content should have the character encoding appropriately marked-up.<br />
</div>
<div class="sub-section"><h3>
<a name="s3.2" id="s3.2"></a><span class="item-no">3.2</span>  Character references/entities
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  Valid character entities take the form <span class="term">&*;</span> where <span class="term">*</span> is <span class="term">#x</span> followed by a hexadecimal number (hexadecimal numeric entity; like <span class="term">&#xA0;</span> for non-breaking space), or alphanumeric like <span class="term">gt</span> (external or named entity; like <span class="term">&nbsp;</span> for non-breaking space), or <span class="term">#</span> followed by a number (decimal numeric entity; like <span class="term">&#160;</span> for non-breaking space). Character entities referring to the soft-hyphen character (the <span class="term">&shy;</span> or <span class="term">\xad</span> character; hexadecimal code-point <span class="term">ad</span> [decimal <span class="term">173</span>]) in attribute values are always replaced with spaces; soft-hyphens in attribute values introduce vulnerabilities in some older versions of the Opera and Mozilla [Firefox] browsers.<br />
+  Valid character entities take the form <span class="term">&*;</span> where <span class="term">*</span> is <span class="term">#x</span> followed by a hexadecimal number (hexadecimal numeric entity; like <span class="term">&#xA0;</span> for non-breaking space), or alphanumeric like <span class="term">gt</span> (external or named entity; like <span class="term">&nbsp;</span> for non-breaking space), or <span class="term">#</span> followed by a number (decimal numeric entity; like <span class="term">&#160;</span> for non-breaking space). Character entities referring to the soft-hyphen character (the <span class="term">&shy;</span> or <span class="term">\xad</span> character; hexadecimal code-point <span class="term">ad</span> [decimal <span class="term">173</span>]) in URL-accepting attribute values are always replaced with spaces; soft-hyphens in attribute values introduce vulnerabilities in some older versions of the Opera and Mozilla [Firefox] browsers.<br />
<br />
  htmLawed (function <span class="term">hl_ent()</span>):<br />
<br />
<br />
  An option like <span class="term">1</span> is useful, e.g., when a writer previews his submission, whereas one like <span class="term">3</span> is useful before content is finalized and made available to all.<br />
<br />
-  <strong>Note:</strong> In the example above, unlike <span class="term"><*></span>, <span class="term"><xml></span> gets considered as a tag (even though there is no HTML element named <span class="term">xml</span>). In general, text matching the regular expression pattern <span class="term"><(/?)([a-zA-Z][a-zA-Z1-6]*)([^>]*?)\s?></span> is considered a tag (phrase enclosed by the angled brackets <span class="term"><</span> and <span class="term">></span>, and starting [with an optional slash preceding] with an alphanumeric word that starts with an alphabet...).<br />
+  <strong>Note:</strong> In the example above, unlike <span class="term"><*></span>, <span class="term"><xml></span> gets considered as a tag (even though there is no HTML element named <span class="term">xml</span>). Thus, the <span class="term">keep_bad</span> parameter's value affects <span class="term"><xml></span> but not <span class="term"><*></span>. In general, text matching the regular expression pattern <span class="term"><(/?)([a-zA-Z][a-zA-Z1-6]*)([^>]*?)\s?></span> is considered a tag (phrase enclosed by the angled brackets <span class="term"><</span> and <span class="term">></span>, and starting [with an optional slash preceding] with an alphanumeric word that starts with an alphabet...), and is subjected to the <span class="term">keep_bad</span> value.<br />
<br />
  Nesting/content rules for each of the 86 elements in htmLawed's default set (see <a href="#s3.3">section 3.3</a>) are defined in function <span class="term">hl_bal()</span>. This means that if a non-standard element besides <span class="term">embed</span> is being permitted through <span class="term">$config["elements"]</span>, the element's tag content will end up getting removed if <span class="term">$config["balance"]</span> is set to <span class="term">1</span>.<br />
<br />
  In some cases, the specs stipulate the number and/or the ordering of the child elements. A <span class="term">table</span> can have 0 or 1 <span class="term">caption</span>, <span class="term">tbody</span>, <span class="term">tfoot</span>, and <span class="term">thead</span>, but they must be in this order: <span class="term">caption</span>, <span class="term">thead</span>, <span class="term">tfoot</span>, <span class="term">tbody</span>.<br />
<br />
  htmLawed currently does not check for conformance to these rules. Note that any non-compliance in this regard will not introduce security vulnerabilities, crash browser applications, or affect the rendering of web-pages.<br />
+<br />
+  With <span class="term">$config["direct_list_nest"]</span> set to <span class="term">1</span>, htmLawed will allow direct nesting of an <span class="term">ol</span> or <span class="term">ul</span> list within another <span class="term">ol</span> or <span class="term">ul</span> without requiring the child list to be within an <span class="term">li</span> of the parent list. While this is not standard-compliant, directly nested lists are rendered properly by almost all browsers. The parameter <span class="term">$config["direct_list_nest"]</span> has no effect if tag-balancing (<a href="#s3.3.3">section 3.3.3</a>) is turned off.<br />
</div>
<div class="sub-section"><h3>
<a name="s3.4" id="s3.4"></a><span class="item-no">3.4</span>  Attributes
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed will only permit attributes described in the HTML specs (including deprecated ones). It also permits some attributes for use with the <span class="term">embed</span> element (the non-standard <span class="term">embed</span> element is supported in htmLawed because of its widespread use), and the the <span class="term">xml:space</span> attribute (valid only in XHTML 1.1). A list of such 111 attributes and the elements they are allowed in is in <a href="#s5.2">section 5.2</a>.<br />
+  htmLawed will only permit attributes described in the HTML specs (including deprecated ones). It also permits some attributes for use with the <span class="term">embed</span> element (the non-standard <span class="term">embed</span> element is supported in htmLawed because of its widespread use), and the the <span class="term">xml:space</span> attribute (valid only in XHTML 1.1). A list of such 111 attributes and the elements they are allowed in is in <a href="#s5.2">section 5.2</a>. Using the <span class="term">$spec</span> argument, htmLawed can be forced to permit custom, non-standard attributes as well as custom rules for standard attributes (<a href="#s2.3">section 2.3</a>).<br />
<br />
  When <span class="term">$config["deny_attribute"]</span> is not set, or set to <span class="term">0</span>, or empty (<span class="term">""</span>), all the 111 attributes are permitted. Otherwise, <span class="term">$config["deny_attribute"]</span> can be set as a list of comma-separated names of the denied attributes. <span class="term">on*</span> can be used to refer to the group of potentially dangerous, script-accepting attributes: <span class="term">onblur</span>, <span class="term">onchange</span>, <span class="term">onclick</span>, <span class="term">ondblclick</span>, <span class="term">onfocus</span>, <span class="term">onkeydown</span>, <span class="term">onkeypress</span>, <span class="term">onkeyup</span>, <span class="term">onmousedown</span>, <span class="term">onmousemove</span>, <span class="term">onmouseout</span>, <span class="term">onmouseover</span>, <span class="term">onmouseup</span>, <span class="term">onreset</span>, <span class="term">onselect</span> and <span class="term">onsubmit</span>.<br />
<br />
<br />
  As a side-note, one may find <span class="term">style: *</span> useful as URLs in <span class="term">style</span> attributes can be specified in a variety of ways, and the patterns that htmLawed uses to identify URLs may mistakenly identify non-URL text.<br />
<br />
+  <span class="term">!</span> can be put in the list of schemes to disallow all protocols as well as <em>local</em> URLs. Thus, with <span class="term">href: http, style: !</span>, '<a href="http://cnn.com" style="background-image: url('local.jpg');">CNN</a>' will become '<a href="http://cnn.com" style="background-image: url('denied:local.jpg');">CNN</a>'.<br />
+<br />
  <strong>Note</strong>: If URL-accepting attributes other than those listed above are being allowed, then the scheme will not be checked unless the attribute name contains the string <span class="term">src</span> (e.g., <span class="term">dynsrc</span>) or starts with <span class="term">o</span> (e.g., <span class="term">onbeforecopy</span>).<br />
<br />
  With <span class="term">$config["safe"] = 1</span>, all URLs are disallowed in the <span class="term">style</span> attribute values.<br />
<a name="s3.4.8" id="s3.4.8"></a><span class="item-no">3.4.8</span>  Inline style properties
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed can check URL schemes and dynamic expressions (to guard against Javascript, etc., script-based insecurities) in inline CSS style property values in the <span class="term">style</span> attributes. (CSS properties like <span class="term">background-image</span> that accept URLs in their values are noted in <a href="#s5.3">section 5.3</a>.) Dynamic CSS expressions that allow scripting in the IE browser, and can be a vulnerability, can be removed from property values by setting <span class="term">$config["css_expression"]</span> to <span class="term">1</span> (default setting).<br />
+  htmLawed can check URL schemes and dynamic expressions (to guard against Javascript, etc., script-based insecurities) in inline CSS style property values in the <span class="term">style</span> attributes. (CSS properties like <span class="term">background-image</span> that accept URLs in their values are noted in <a href="#s5.3">section 5.3</a>.) Dynamic CSS expressions that allow scripting in the IE browser, and can be a vulnerability, can be removed from property values by setting <span class="term">$config["css_expression"]</span> to <span class="term">1</span> (default setting). Note that when <span class="term">$config["css_expression"]</span> is set to <span class="term">1</span>, htmLawed will remove <span class="term">/*</span> from the <span class="term">style</span> values.<br />
<br />
  <strong>Note</strong>: Because of the various ways of representing characters in attribute values (URL-escapement, entitification, etc.), htmLawed might alter the values of the <span class="term">style</span> attribute values, and may even falsely identify dynamic CSS expressions and URL schemes in them. If this is an important issue, checking of URLs and dynamic expressions can be turned off (<span class="term">$config["schemes"] = "...style:*..."</span>, see <a href="#s3.4.3">section 3.4.3</a>, and <span class="term">$config["css_expression"] = 0</span>). Alternately, admins can use their own custom function for finer handling of <span class="term">style</span> values through the <span class="term">hook_tag</span> parameter (see <a href="#s3.4.9">section 3.4.9</a>).<br />
<br />
<br />
  It is possible to utilize a custom hook function to alter the tag content htmLawed has finalized (i.e., after it has checked/corrected for required attributes, transformed attributes, lower-cased attribute names, etc.).<br />
<br />
-  When <span class="term">$config</span> parameter <span class="term">hook_tag</span> is set to the name of a function, htmLawed (function <span class="term">hl_tag()</span>) will pass on the element name, and the <em>finalized</em> attribute name-value pairs as array elements to the function. The function is expected to return the full opening tag string like <span class="term"><element_name attribute_1_name="attribute_1_value"...></span> (for empty elements like <span class="term">img</span> and <span class="term">input</span>, the element-closing slash <span class="term">/</span> should also be included).<br />
+  When <span class="term">$config</span> parameter <span class="term">hook_tag</span> is set to the name of a function, htmLawed (function <span class="term">hl_tag()</span>) will pass on the element name, and, in the case of an opening tag, the <em>finalized</em> attribute name-value pairs as array elements to the function. The function, after completing a task such as filtering or tag transformation, will typically return an empty string, the full opening tag string like <span class="term"><element_name attribute_1_name="attribute_1_value"...></span> (for empty elements like <span class="term">img</span> and <span class="term">input</span>, the element-closing slash <span class="term">/</span> should also be included), etc.<br />
+<br />
+  Any <span class="term">hook_tag</span> function, since htmLawed version 1.1.11, also receives names of elements in closing tags, such as <span class="term">a</span> in the closing <span class="term"></a></span> tag of the element <span class="term"><a href="http://cnn.com">CNN</a></span>. Unlike for opening tags, no other value (i.e., the attribute name-value array) is passed to the function since a closing tag contains only element names. Typically, the function will return an empty string or a full closing tag (like <span class="term"></a></span>).<br />
<br />
  This is a <strong>powerful functionality</strong> that can be exploited for various objectives: consolidate-and-convert inline <span class="term">style</span> attributes to <span class="term">class</span>, convert <span class="term">embed</span> elements to <span class="term">object</span>, permit only one <span class="term">caption</span> element in a <span class="term">table</span> element, disallow embedding of certain types of media, <strong>inject HTML</strong>, use <a href="http://csstidy.sourceforge.net">CSSTidy</a> to sanitize <span class="term">style</span> attribute values, etc.<br />
<br />
  As an example, the custom hook code below can be used to force a series of specifically ordered <span class="term">id</span> attributes on all elements, and a specific <span class="term">param</span> element inside all <span class="term">object</span> elements:<br />
<br />
-<code class="code">    function my_tag_function($element, $attribute_array){</code>
+<code class="code">    function my_tag_function($element, $attribute_array=0){</code>
+<br />
+<br />
+
+<code class="code">      // If second argument is not received, it means a closing tag is being handled</code>
+<br />
+
+<code class="code">      if(is_numeric($attribute_array)){</code>
+<br />
+
+<code class="code">        return "</$element>";</code>
+<br />
+
+<code class="code">      }</code>
+<br />
<br />
<code class="code">      static $id = 0;</code>
<code class="code">      }</code>
<br />
+<br />
+
+<code class="code">      static $empty_elements = array('area'=>1, 'br'=>1, 'col'=>1, 'embed'=>1, 'hr'=>1, 'img'=>1, 'input'=>1, 'isindex'=>1, 'param'=>1);</code>
+<br />
+<br />
<code class="code">      return "<{$element}{$string}". (isset($in_array($element, $empty_elements) ? ' /' : ''). '>'. $new_element;</code>
<br />
<br />
  htmLawed allows an admin to use <span class="term">$config["safe"]</span> to auto-adjust multiple <span class="term">$config</span> parameters (such as <span class="term">elements</span> which declares the allowed element-set), which otherwise would have to be manually set. The relevant parameters are indicated by <span class="term">"</span> in <a href="#s2.2">section 2.2</a>). Thus, one can pass the <span class="term">$config</span> argument with a simpler value.<br />
<br />
-  With the value of <span class="term">1</span>, htmLawed considers <span class="term">CDATA</span> sections and HTML comments as plain text, and prohibits the <span class="term">applet</span>, <span class="term">embed</span>, <span class="term">iframe</span>, <span class="term">object</span> and <span class="term">script</span> elements, and the <span class="term">on*</span> attributes like <span class="term">onclick</span>. ( There are <span class="term">$config</span> parameters like <span class="term">css_expression</span> that are not affected by the value set for <span class="term">safe</span> but whose default values still contribute towards a more <em>safe</em> output.) Further, URLs with schemes (see <a href="#s3.4.3">section 3.4.3</a>) are neutralized so that, e.g., <span class="term">style="moz-binding:url(http://danger)"</span> becomes <span class="term">style="moz-binding:url(denied:http://danger)"</span> while <span class="term">style="moz-binding:url(ok)"</span> remains intact.<br />
+  With the value of <span class="term">1</span>, htmLawed considers <span class="term">CDATA</span> sections and HTML comments as plain text, and prohibits the <span class="term">applet</span>, <span class="term">embed</span>, <span class="term">iframe</span>, <span class="term">object</span> and <span class="term">script</span> elements, and the <span class="term">on*</span> attributes like <span class="term">onclick</span>. ( There are <span class="term">$config</span> parameters like <span class="term">css_expression</span> that are not affected by the value set for <span class="term">safe</span> but whose default values still contribute towards a more <em>safe</em> output.) Further, URLs with schemes (see <a href="#s3.4.3">section 3.4.3</a>) are neutralized so that, e.g., <span class="term">style="moz-binding:url(http://danger)"</span> becomes <span class="term">style="moz-binding:url(denied:http://danger)"</span>.<br />
<br />
  Admins, however, may still want to completely deny the <span class="term">style</span> attribute, e.g., with code like<br />
<br />
<code class="code">    $processed = htmLawed($text, array('safe'=>1, 'deny_attribute'=>'style'));</code>
<br />
<br />
+  Permitting the <span class="term">style</span> attribute brings in risks of <em>click-jacking</em>, etc. CSS property values can render a page non-functional or be used to deface it. Except for URLs, dynamic expressions, and some other things, htmLawed does not completely check <span class="term">style</span> values. It does provide ways for the code-developer implementing htmLawed to do such checks through the <span class="term">$spec</span> argument, and through the <span class="term">hook_tag</span> parameter (see <a href="#s3.4.8">section 3.4.8</a> for more). Disallowing style completely and relying on CSS classes and stylesheet files is recommended.<br />
+<br />
  If a value for a parameter auto-set through <span class="term">safe</span> is still manually provided, then that value can over-ride the auto-set value. E.g., with <span class="term">$config["safe"] = 1</span> and <span class="term">$config["elements"] = "*+script"</span>, <span class="term">script</span>, but not <span class="term">applet</span>, is allowed.<br />
<br />
  A page illustrating the efficacy of htmLawed's anti-XSS abilities with <span class="term">safe</span> set to <span class="term">1</span> against XSS vectors listed by <a href="http://ha.ckers.org/xss.html">RSnake</a> may be available <a href="http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed/rsnake/RSnakeXSSTest.htm">here</a>.<br />
<a name="s3.9" id="s3.9"></a><span class="item-no">3.9</span>  Retaining non-HTML tags in input with mixed markup
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  htmLawed does not remove certain characters that
though invalid are nevertheless discouraged in HTML documents as per the specs (see <a href="#s5.1">section 5.1</a>). This can be utilized to deal with input that contains mixed markup. Input that may have HTML markup as well as some other markup that is based on the <span class="term"><</span>, <span class="term">></span> and <span class="term">&</span> characters is considered to have mixed markup. The non-HTML markup can be rather proprietary (like markup for emoticons/smileys), or standard (like MathML or SVG). Or it can be programming code meant for execution/evaluation (such as embedded PHP code).<br />
+  htmLawed does not remove certain characters that
, though invalid, are nevertheless <em>discouraged</em> in HTML documents as per the specifications (see <a href="#s5.1">section 5.1</a>). This can be utilized to deal with input that contains mixed markup. Input that may have HTML markup as well as some other markup that is based on the <span class="term"><</span>, <span class="term">></span> and <span class="term">&</span> characters is considered to have mixed markup. The non-HTML markup can be rather proprietary (like markup for emoticons/smileys), or standard (like MathML or SVG). Or it can be programming code meant for execution/evaluation (such as embedded PHP code).<br />
<br />
  To deal with such mixed markup, the input text can be pre-processed to hide the non-HTML markup by specifically replacing the <span class="term"><</span>, <span class="term">></span> and <span class="term">&</span> characters with some of the HTML-discouraged characters (see <a href="#s3.1.2">section 3.1.2</a>). Post-htmLawed processing, the replacements are reverted.<br />
<br />
<a name="s4.1" id="s4.1"></a><span class="item-no">4.1</span>  Support
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  A careful re-reading of this documentation will very likely answer your questions.<br />
+  A careful reading of this documentation may provide an answer.<br />
<br />
  Software updates and forum-based community-support may be found at <a href="http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed">http://www.bioinformatics.org/phplabware/internal_utilities/htmLawed</a>. For general PHP issues (not htmLawed-specific), support may be found through internet searches and at <a href="http://php.net">http://php.net</a>.<br />
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
  See <a href="#s2.8">section 2.8</a>.<br />
-<br />
-  Readers are advised to cross-check information given in this document.<br />
</div>
<div class="sub-section"><h3>
<a name="s4.3" id="s4.3"></a><span class="item-no">4.3</span>  Change-log
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  (The release date for the downloadable package of files containing documentation, demo script, test-cases, etc., besides the <span class="term">htmLawed.php</span> file may be updated independently if the secondary files are revised.)<br />
+  (The release date for the downloadable package of files containing documentation, demo script, test-cases, etc., besides the <span class="term">htmLawed.php</span> file, may be updated without a change-log entry if the secondary files, but not htmLawed per se, are revised.)<br />
<br />
  <em>Version number - Release date. Notes</em><br />
<br />
+  1.1.19 - 19 January 2015. Fix for a bug in cleaning of soft-hyphens in URL values, etc.<br />
+<br />
+  1.1.18 - 2 August 2014. Fix for a potential security vulnerability arising from specially encoded text with serial opening tags<br />
+<br />
+  1.1.17 - 11 March 2014. Removed use of PHP function preg_replace with <span class="term">e</span> modifier for compatibility with PHP 5.5<br />
+<br />
+  1.1.16 - 29 August 2013. Fix for a potential security vulnerability arising from specially encoded space characters in URL schemes/protocols<br />
+<br />
+  1.1.15 - 11 August 2013. Improved tidying/prettifying functionality<br />
+<br />
+  1.1.14 - 8 August 2012. Fix for possible segmental loss of incremental indentation during <span class="term">tidying</span> when <span class="term">balance</span> is disabled; fix for non-effectuation under some circumstances of a corrective behavior to preserve plain text within elements like <span class="term">blockquote</span>.<br />
+<br />
+  1.1.13 - 22 July 2012. Added feature allowing use of custom, non-standard attributes or custom rules for standard attributes<br />
+<br />
+  1.1.12 - 5 July 2012. Fix for a bug in identifying an unquoted value of the <span class="term">face</span> attribute<br />
+<br />
+  1.1.11 - 5 June 2012. Fix for possible problem with handling of multi-byte characters in attribute values in an mbstring.func_overload environment. <span class="term">$config["hook_tag"]</span>, if specified, now receives names of elements in closing tags.<br />
+<br />
+  1.1.10 - 22 October 2011. Fix for a bug in the <span class="term">tidy</span> functionality that caused the entire input to be replaced with a single space; new parameter, <span class="term">$config["direct_list_nest"]</span> to allow direct descendence of a list in a list. (5 April 2012. Dual licensing from LGPLv3 to LGPLv3 and GPLv2+.)<br />
+<br />
+  1.1.9.5 - 6 July 2011. Minor correction of a rule for nesting of <span class="term">li</span> within <span class="term">dir</span><br />
+<br />
+  1.1.9.4 - 3 July 2010. Parameter <span class="term">schemes</span> now accepts <span class="term">!</span> so any URL, even a local one, can be <em>denied</em>. An issue in which a second URL value in <span class="term">style</span> properties was not checked was fixed.<br />
+<br />
+  1.1.9.3 - 17 May 2010. Checks for correct nesting of <span class="term">param</span><br />
+<br />
+  1.1.9.2 - 26 April 2010. Minor fix regarding rendering of denied URL schemes<br />
+<br />
+  1.1.9.1 - 26 February 2010. htmLawed now uses the LGPL version 3 license; support for <span class="term">flashvars</span> attribute for <span class="term">embed</span><br />
+<br />
+  1.1.9 - 22 December 2009. Soft-hyphens are now removed only from URL-accepting attribute values<br />
+<br />
  1.1.8.1 - 16 July 2009. Minor code-change to fix a PHP error notice<br />
<br />
  1.1.8 - 23 April 2009. Parameter <span class="term">deny_attribute</span> now accepts the wild-card <span class="term">*</span>, making it simpler to specify its value when all but a few attributes are being denied; fixed a bug in interpreting <span class="term">$spec</span><br />
<br />
  1.1.1 - 27 September 2008. Better nesting correction when omitable closing tags are absent<br />
<br />
-  1.1 - 29 June 2008. <span class="term">$config["hook_tag"]</span> and <span class="term">$config["format"]</span> introduced for custom tag/attribute check/modification/injection and output compaction/beautification; fixed a regex-in-$spec parsing bug<br />
+  1.1 - 29 June 2008. <span class="term">$config["hook_tag"]</span> and <span class="term">$config["tidy"]</span> introduced for custom tag/attribute check/modification/injection and output compaction/beautification; fixed a regex-in-$spec parsing bug<br />
<br />
-  1.0.9 - 11 June 2008. Fixed bug in invalid HTML code-point entity check<br />
+  1.0.9 - 11 June 2008. Fix for a bug in checks for invalid HTML code-point entities<br />
<br />
-  1.0.8 - 15 May 2008. <span class="term">bordercolor</span> attribute for <span class="term">table</span>, <span class="term">td</span> and <span class="term">tr</span><br />
+  1.0.8 - 15 May 2008. Permit <span class="term">bordercolor</span> attribute for <span class="term">table</span>, <span class="term">td</span> and <span class="term">tr</span><br />
<br />
  1.0.7 - 1 May 2008. Support for <span class="term">wmode</span> attribute for <span class="term">embed</span>; <span class="term">$config["show_setting"]</span> introduced; improved <span class="term">$config["elements"]</span> evaluation<br />
<br />
<br />
  1.0.4 - 10 March 2008. Improved corrections for <span class="term">blockquote</span>, <span class="term">form</span>, <span class="term">map</span> and <span class="term">noscript</span><br />
<br />
-  1.0.3 - 3 March 2008. Character entities for soft-hyphens are now replaced with spaces (instead of being removed); a bug allowing <span class="term">td</span> directly inside <span class="term">table</span> fixed; <span class="term">safe</span> <span class="term">$config</span> parameter added<br />
+  1.0.3 - 3 March 2008. Character entities for soft-hyphens are now replaced with spaces (instead of being removed); fix for a bug allowing <span class="term">td</span> directly inside <span class="term">table</span>; <span class="term">$config["safe"]</span> introduced<br />
<br />
  1.0.2 - 13 February 2008. Improved implementation of <span class="term">$config["keep_bad"]</span><br />
<br />
<br />
  Upgrading is as simple as replacing the previous version of <span class="term">htmLawed.php</span> (assuming it was not modified for customized features). As htmLawed output is almost always used in static documents, upgrading should not affect old, finalized content.<br />
<br />
+  <strong>Important</strong>  The following upgrades may affect the functionality of a specific htmLawed installation:<br />
+<br />
+  (1) From version 1.1-1.1.10 to 1.1.11 (or later), if a <span class="term">hook_tag</span> function is in use: In version 1.1.11, elements in closing tags (and not just the opening tags) are also passed to the function. There are no attribute names/values to pass, so a <span class="term">hook_tag</span> function receives only the element name. The <span class="term">hook_tag</span> function therefore may have to be edited. See <a href="#s3.4.9">section 3.4.9</a>.<br />
+<br />
  Old versions of htmLawed may be available online. E.g., for version 1.0, check <a href="http://www.bioinformatics.org/phplabware/downloads/htmLawed1.zip">http://www.bioinformatics.org/phplabware/downloads/htmLawed1.zip</a>, for 1.1.1, htmLawed111.zip, and for 1.1.10, htmLawed1110.zip.<br />
</div>
<a name="s4.6" id="s4.6"></a><span class="item-no">4.6</span>  Comparison with <span class="term">HTMLPurifier</span>
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  The HTMLPurifier PHP library by Edward Yang is a very good HTML filtering script that uses object oriented PHP code. Compared to htmLawed, it:<br />
+  The HTMLPurifier PHP library by Edward Yang is a very good HTML filtering script that uses object oriented PHP code. Compared to htmLawed, it (as of year 2010):<br />
<br />
  *  does not support PHP versions older than 5.0 (HTMLPurifier dropped PHP 4 support after version 2)<br />
<br />
<a name="s4.10" id="s4.10"></a><span class="item-no">4.10</span>  Acknowledgements
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  Bryan Blakey, Ulf Harnhammer, Gareth Heyes, Lukasz Pilorz, Shelley Powers, Edward Yang, and many anonymous users.<br />
+  Nicholas Alipaz, Bryan Blakey, Pádraic Brady, Dac Chartrand, Ulf Harnhammer, Gareth Heyes, Klaus Leithoff, Lukasz Pilorz, Shelley Powers, Psych0tr1a, Lincoln Russell, Tomas Sykorka, Harro Verton, Edward Yang, and many anonymous users.<br />
<br />
  Thank you!<br />
<a name="s5.2" id="s5.2"></a><span class="item-no">5.2</span>  Valid attribute-element combinations
</h3><span class="totop"><a href="#peak">(to top)</a></span><br style="clear: both;" />
<br />
-  Valid attribute-element combinations as per W3C specs.<br />
+  Valid attribute-element combinations as per <a href="http://www.w3c.org">W3C</a> specs.<br />
<br />
  *  includes deprecated attributes (marked <span class="term">^</span>), attributes for the non-standard <span class="term">embed</span> element (marked <span class="term">*</span>), and the proprietary <span class="term">bordercolor</span> (marked <span class="term">~</span>)<br />
  *  only non-frameset, HTML body elements<br />
  disabled - button, input, optgroup, option, select, textarea<br />
  enctype - form<br />
  face - font<br />
+  flashvars* - embed<br />
  for - label<br />
  frame - table<br />
  frameborder - iframe<br />
<br />
  <strong>Function arguments</strong> for htmLawed are:<br />
<br />
-  *  <span class="term">$in</span> - 1st argument; a text string; the <strong>input text</strong> to be processed. Any extraneous slashes added by PHP when <em>magic quotes</em> are enabled should be removed beforehand using PHP's <span class="term">stripslashes()</span> function.<br />
+  *  <span class="term">$in</span> - first argument; a text string; the <strong>input text</strong> to be processed. Any extraneous slashes added by PHP when <em>magic quotes</em> are enabled should be removed beforehand using PHP's <span class="term">stripslashes()</span> function.<br />
<br />
-  *  <span class="term">$config</span> - 2nd argument; an associative array; optional (named <span class="term">$C</span> in htmLawed code). The array has keys with names like <span class="term">balance</span> and <span class="term">keep_bad</span>, and the values, which can be boolean, string, or array, depending on the key, are read to accordingly set the <strong>configurable parameters</strong> (indicated by the keys). All configurable parameters receive some default value if the value to be used is not specified by the user through <span class="term">$config</span>. <em>Finalized</em> <span class="term">$config</span> is thus a filtered and possibly larger array.<br />
+  *  <span class="term">$config</span> - second argument; an associative array; optional; named <span class="term">$C</span> within htmLawed code. The array has keys with names like <span class="term">balance</span> and <span class="term">keep_bad</span>, and the values, which can be boolean, string, or array, depending on the key, are read to accordingly set the <strong>configurable parameters</strong> (indicated by the keys). All configurable parameters receive some default value if the value to be used is not specified by the user through <span class="term">$config</span>. <em>Finalized</em> <span class="term">$config</span> is thus a filtered and possibly larger array.<br />
<br />
-  *  <span class="term">$spec</span> - 3rd argument; a text string; optional. The string has rules, written in an htmLawed-designated format, <strong>specifying</strong> element-specific attribute and attribute value restrictions. Function <span class="term">hl_spec()</span> is used to convert the string to an associative-array for internal use. <em>Finalized</em> <span class="term">$spec</span> is thus an array.<br />
+  *  <span class="term">$spec</span> - third argument; a text string; optional. The string has rules, written in an htmLawed-designated format, <strong>specifying</strong> element-specific attribute and attribute value restrictions. Function <span class="term">hl_spec()</span> is used to convert the string to an associative-array, named <span class="term">$S</span> within htmLawed code, for internal use. <em>Finalized</em> <span class="term">$spec</span> is thus an array.<br />
<br />
  <em>Finalized</em> <span class="term">$config</span> and <span class="term">$spec</span> are made <strong>global variables</strong> while htmLawed is at work. Values of any pre-existing global variables with same names are noted, and their values are restored after htmLawed finishes processing the input (to capture the <em>finalized</em> values, the <span class="term">show_settings</span> parameter of <span class="term">$config</span> should be used). Depending on <span class="term">$config</span>, another global variable <span class="term">hl_Ids</span>, to track <span class="term">id</span> attribute values for uniqueness, may be set. Unlike the other two variables, this one is not reset (or unset) post-processing.<br />
<br />
<br />
  After this <em>initial processing</em> <span class="term">htmLawed()</span> identifies tags using regex and processes them with the help of <span class="term">hl_tag()</span> --  a large function that analyzes tag content, filtering it as per HTML standards, <span class="term">$config</span> and <span class="term">$spec</span>. Among other things, <span class="term">hl_tag()</span> transforms deprecated elements using <span class="term">hl_tag2()</span>, removes attributes from closing tags, checks attribute values as per <span class="term">$spec</span> rules using <span class="term">hl_attrval()</span>, and checks URL protocols using <span class="term">hl_prot()</span>. <span class="term">htmLawed()</span> performs tag balancing and nesting checks with a call to <span class="term">hl_bal()</span>, and optionally compacts/beautifies the output with proper white-spacing with a call to <span class="term">hl_tidy()</span>. The latter temporarily replaces white-space, and <span class="term"><</span>, <span class="term">></span> and <span class="term">&</span> characters inside <span class="term">pre</span>, <span class="term">script</span> and <span class="term">textarea</span> elements, and HTML comments and CDATA sections with control characters (code-points <span class="term">1</span> to <span class="term">5</span>, and <span class="term">7</span>).<br />
<br />
-  htmLawed permits the use of custom code or <strong>hook functions</strong> at two stages. The first, called inside <span class="term">htmLawed()</span>, allows the input text as well as the finalized
$config and $spec values to be altered right after the initial processing (see <a href="#s3.7">section 3.7</a>). The second is called by <span class="term">hl_tag()</span> once the tag content is finalized (see <a href="#s3.4.9">section 3.4.9</a>).<br />
+  htmLawed permits the use of custom code or <strong>hook functions</strong> at two stages. The first, called inside <span class="term">htmLawed()</span>, allows the input text as well as the finalized
<span class="term">$config</span> and <span class="term">$spec</span> values to be altered right after the initial processing (see <a href="#s3.7">section 3.7</a>). The second is called by <span class="term">hl_tag()</span> once the tag content is finalized (see <a href="#s3.4.9">section 3.4.9</a>).<br />
<br />
-  Being dictated by the external and stable HTML standard, htmLawed's objective is very clear-cut and less concerned with tweakability. The code is only minimally annotated with comments -- it is not meant to instruct; PHP developers familiar with the HTML specs will see the logic, and others can always refer to the htmLawed documentation. The compact structuring of the statements is meant to aid in quickly grasping the logic, at least when viewed with code syntax highlighted.
+  The functionality of htmLawed is dictated by the external HTML standard. It is thus coded for a clear-cut objective with not much concern for tweakability. The code is only minimally annotated with comments -- it is not meant to instruct; PHP developers familiar with the HTML specifications will see the logic, and others can always refer to the htmLawed documentation. The compact structuring of the statements is meant to aid a quick grasp of the logic.
</div>
</div>
<br />
-<hr /><br /><br /><span class="subtle"><small>HTM version of <em><a href="htmLawed_README.txt">htmLawed_README.txt</a></em> generated on
23 Apr, 2009 using <a href="http://www.bioinformatics.org/phplabware/internal_utilities">rTxt2htm</a> from PHP Labware</small></span>
+<hr /><br /><br /><span class="subtle"><small>HTM version of <em><a href="htmLawed_README.txt">htmLawed_README.txt</a></em> generated on
19 Jan, 2015 using <a href="http://www.bioinformatics.org/phplabware/internal_utilities">rTxt2htm</a> from PHP Labware</small></span>
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projects / quix0rs-gnu-social.git / blobdiff